Water sensitive flow monitor



Sept. 15, 1970 ADAMS ET AL 3,528,547

WATER SENSITIVE FLOW MONITOR I FilBd Jan. 14, 1969 2 Sheets-Sheet 1INVENTORS ROGER E. ADAMS SAMUEL]. LYDA 11) um+m Sept. 15, 1 970 ADAMSETAL 3,528,547

WATER SENSITIVE FLOW MONITOR Filed Jan. 14, 1969 2 Sheets-Sheet IINVENTORS ROGER E. ADAMS SAMUEL I. LYDA United States Patent O 3,528,547WATER SENSITIVE FLOW MONITOR Roger E. Adams, San Jose, and Samuel J.Lyda, Fremont, Calif, assignors to Velcon Filters Inc., San Jose,

Calif., a corporation of California Filed Jan. 14, 1969, Ser. No.791,077 Int. Cl. B01d 29/00 U.S. Cl. 210-96 9 Claims ABSTRACT OF THEDISCLOSURE A filter and flow monitor for sensing the presence of freewater in a transient flow of fluid comprising an inlet for the fluid tobe monitored, an outlet for the monitored fluid, and a mass of waterswellable granular algin material disposed between the inlet and outletthrough which the fluid is caused to pass. Upon the presence of apredetermined concentration of water in the fluid being tested, thewater swellable granular material will swell to completely block theflow of any fluid therethrough.

BACKGROUND OF THE INVENTION Present day fuel employed for aircraft istypically of a high quality; however, the aircraft fueling systems andequipment are not without faults. Even though efficient filtration andwater separation equipment is employed whenever fuel is transferred fromone point to another point, so that under normal operating conditionsthe fuel will be dispensed with a low solids content and practically noundissolved or free water content, there is no guarantee that eachaircraft refueled has acceptable fuel under all conditions and at eachrefueling.

Fuel water separator systems include some type of coalescer and filterseparator elements which retain the solid contaminants contained in thefuel flowing through the system and are effective to coalesce and removethe water content therein. In removing the solid contaminants of thetransient fuel, the elements gradually olfer increased resistance to theflow of fuel until the attained pressure drop across the element becomesgreater than the system pressure can attain. In the event the element isnot replaced before this occurrence, the element will malfunction anddischarge into the aircraft fuel tanks, a large quantity ofcontaminants, both solid and water. Also, it has been found that incertain instances, the fuel being passed through the fuel waterseparators may contain surfactants and the like, causing the coalescerelements to be inoperative or ineffective in coalescing and removing thewater content of the fuel.

It will be appreciated that aircraft operation with such contaminatedfuel could prove disastrous, since normal airborne filters are designedto merely remove small traces of solid contaminants and no water. Largeamounts of contaminants will quickly plug up these airborne filters,causing the bypass valves in the filters to open, allowing thecontaminated fuel to adversely wear the associated pumps, plug theservos of the fuel control, and to permit the water in the fuel tofreeze in the fuel lines causing engine malfunction, thereby endangeringlife and property.

It is an object of the present invention to produce a water sensitivefilter and flow monitor which will block the flow of fuel containing anunacceptable concentration of free water therein.

Another object of the invention is to provide a water sensitive filterand flow monitor which will react immediately to contamination passingtherethrough by registering an increase in pressure differential, andcompletely blocking the flow therethrough at normal operating pressure.

A further object of the invention is to produce a Water sensitive filterand monitor which will not offer an excessive pressure drop to flow whenoperated with fuel of acceptable contamination levels.

SUMMARY The above objects and advantages of the invention may beachieved by a water sensitive fluid flow monitor comprising an inlet forthe fluid to be monitored; an outlet for the monitored fluid; a confinedpassageway establishing communication between the inlet and the outlet;and a mass of water sensitive granular material swellable upon thepresence of water to block the flow of fluid between the inlet and theoutlet.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of theinvention will become manifest to those skilled in the art by readingthe following detailed description of an embodiment of the inventionwhen considered in the light of the accompanying drawings, in which:

FIG. 1 is a sectional view of a fuel monitoring device incorporating thewater sensitive flow monitors constructed in accordance with theinvention;

FIG. 2 is an elevational view of a water sensitive flow monitor of thetype illustrated in FIG. 1;

FIG. 3 is an elevational view of the monitor illustrated in FIG. 2 withportions cut away to more clearly illustrate the structure; and

FIG. 4 is a sectional view taken along line 44 of FIG. 2.

DESCRIPTION .OF THE PREFERRED EMBODIMENT Referring to FIG. 1 of thedrawings, there is illustrated a vessel generally indicated by referencenumber having a base member 12 and an upper closure 14. The open end ofthe upper closure 14 is provided with an outwardly extending flange 16provided with an array of apertures alignable with similar apertures inthe base member 12 to receive nut and bolt fastening means 18. Toproduce a fluid-tight seal between the base member 12 and the upperclosure 14, a gasket ring 20' is provided. It will be apparent thataccess can be had to the interior of the vessel 10 by removing the nutand bolt fastening means 18 and removing the upper closure 14 from thebase member 12. The vessel 10 is provided with a fluid inlet 22 and afluid outlet 24.

A manifold 26 is mounted on the base member 12 in communication with theoutlet 24. A plurality of water sensitive fluid flow monitors or fuseelements 28 is suitably attached to the base member 12 and retained inposition by a retainer plate 30 which is operatively connected to thebase member 12 by an upstanding bolt 32 and an associated nut 34. Thedirection of fluid flow through the vessel 10 is indicated by thearrows. Each of the fuse elements 28, as clearly illustrated in FIGS. 2,3 and 4 is provided with a centrally disposed helically formed steelspring 36 which may be formed of stainless steel wire of the order of0.040 inch in diameter and having five coils per inch. A cylindricalliquid pervious sleeve 38 formed of a screen of a one hundred mesh sizeof Monel metal is disposed concentrically about the spring 36. A layer40 of a filter paper is wrapped concentrically about the screen sleeve38.

A wrap 42 of porous fiber glass material is disposed in concentricspaced relation about the outer surface of the wrap 40 of filter paper.Acceptable results have been obtained by employing fiber glass materialof the type commercially sold by Owens-Corning Fiberglas Corporation anddesignated as type AA wherein the fibers are bonded together with acured phenolic binder such as for example, phenol formaldehyde. It hasbeen found desirable to maintain a spacing of approximately inch betweenthe outer surface of paper layer 40 and the inner surface of the fiberglass layer 42. A second layer of wrap 44 of porous fiber glass materialis disposed immediately adjacent the outer surface of the wrap 42. Thewrap 44 is preferably formed of fiber glass material of the typecommercially sold by Owens-Corning Fiberglas Corporation and designatedas type B wherein the fibers are bonded together with a cured phenolicbinder such as for example, phenol formaldehyde.

Formed about the entire outer surface of the outermost wrap 44, there isa plastic cylindrical screen 46 of rather large mesh. The material usedin fabricating the cylindrical screen 46 must be inert the fluids beingtreated and polyethylene has been found satisfactory for use withhydrocarbon fluids such as jet aviation fuel. It has been founddesirable to employ the outermost plastic screen 46 to impart structuralintegrity to the over-all element. The upper end of the assembly, thusfar described, is closed off by a plastic end cap 48, while the oppositeend is provided with an aperture plastic end cap 50. Before the end cap50 is formed, and after the formation of the end cap 48, a granularwater swellable material 52 is poured into the space between the outersurface of the layer 40 and the inner surface of the wraps 42. The spacetherebetween is completely filled and to assure proper filling, theassembly may be vibrated to cause the graular 7 material 52 to evenlycompact. Finally, an adequate amount of a quick-set resin, for example,is disposed in the open end of the material 52 and after this materialis set, the assembly is turned over and a lower end is provided with asuitable end cap 50. Then an annular sealing gasket 54 is applied to theouter surface to the end cap 50 to assure a liquid tight contact betweenthe element 28 and the manifold 26.

The end caps 48 and 50 are each formed in a similar fashion, bydisposing the respective end of the assembly in a suitable die employinga suitable hardenable resin material therein. The end portions of thecenter spring 36, cylindrical screen 38, the filter paper layer 40, thefiber glass wraps 42 and 44, and the screen 46 are actually immersedinto the plastic material while it is in liquid form. The resin is thenallowed to set or cure, and thereafter the assembly is removed from theend cap forming die. As pointed out hereinabove, the end caps 48 and 50are typically formed in two separate operations. Satisfactory resultshave been achieved by forming the end caps of a polyester resin.

It has been discovered that excellent results have been achieved byusing algin or sodium alginate as the granular water swellable material52, such as for example, a product commercially available under thetrademark Kelzan manufactured and sold by Kelco Company. Algin or sodiumalkinate is a hydrophilic material derived from certain marine algaecommonly known as brown algae. Typically, algin is extracted from thealgae by treatment with soda ash or a similar alkali, after which it isusually separated from the cellulose present in the plant and thenbleached, purified, dried and converted into the desired particle size.The term algin is used to designate the water soluble derivative ofalginic acid, the most common of which is sodium alginate. Alginic acidis found to be only slightly soluble in water, is soluble in certainorganic solvents, and is capable of absorbing many times its weight ofwater.

In operation, the fluid to be treated, such as JP-4 or JP-S jet fuel iscaused to enter the vessel 10, illustrated in FIG. 1, through the inlet22, and is then caused to flow to the outlet 24 through the monitor orfuse elements 28. It will be noted that the fluid flow is from theoutside to the inside of the fuse elements 28, and thence to the outletthrough the manifold 26. Typically, the system illustrated in FIG. 1 isdisposed in fluid communication between a water fuel separator unit andan aircraft to which clean dry fuel is to be delivered. It will beappreciated that the system can be stationary in nature, or can bemounted in a refueler vehicle and be an integral part of a mobilerefueling system. In any event, during the operation of the system, themonitor or fuse elements 28 are inert to clean dry fuel containing noundissolved water. When traces or slugs of free water in excess of apredetermined level pass into the vessel 10, the monitor or fuseelements 28 will sense the contamination immediately and register apractically instantaneous increase in pressure drop. This pressure dropoccurs because the individual granules of the algin material 52apparently soften and tend to join with other adjacent granules to forma composite mass having continuously decreasing pore sizes betweenadjacent granules until the pores are completely closed, completelycutting off the flow of fuel therethrough. The softened granules of thealgin material 52 appears to form a gelatinous mass which cooperateswith the filter paper 40 to effect the desired objective of stopping theflow of fuel through the elements 28. The bursting strength of theelements 28 is greater than the average system pressure output. Thesystem, therefore, permits acceptable dry fuel to pass therethrough, butonce undesired water content is present, the elements 28 will close,thereby militating against the passage of any fluid therethrough.Accordingly, the invention has produced a fuel monitoring systememploying a granular material which will permit acceptable fuel to pass,but once contaminated fuel is present, the system completely blocks anyflow therethrough.

In conclusion, it will be appreciated that the invention is effective tosense the presence of contamination in the fuel by increasing theresistance to flow through the system which increase is noted by readingan associated pressure gauge. Also, continuing flow of the contaminatedfuel will cause the monitor or fuse elements 28 to completely block theflow of any fluid therethrough.

The number, length, and diameter of the monitor or fuse elements 28within a vessel 10 will determine the flow rating of the over-allsystem.

A further feature of the invention is that while the elements 28 areparticularly sensitive to water content of the transient fluid, it willbe appreciated that particulate contaminants in the fluid being treatedwill be removed from the transient fluid and blocked primarily by thelayers 42 and 44 of fiber glass material.

In conclusion, it will be seen from the above description that the watersensitive fluid flow monitoring device is simple in construction andinexpensive to manufacture, and is reliable to stop the flow of a fluidif it contains an amount of free water over a predetermined level.

In accordance with the provisions of the patent statutes, we haveexplained the principle and mode of operation of our invention and haveillustrated and described what we now consider to represent its bestembodiment. However, it is to be understood that within the spirit andscope of the appended claims the invention may be practiced otherwisethan as specifically illustrated and described.

We claim:

1. A water sensitive flow monitor element comprising:

an inlet for the fluid to be monitored;

an outlet for the monitored fluid;

a confined passageway establishing communication between said inlet andsaid outlet; and

a mass of algin material disposed within said passage,

permitting the passage of hydrocarbon fluids therethrough while swellingupon the presence of free water to block the flow of fluid between saidinlet and said outlet.

2. The invention defined in claim 1 wherein said algin material isgranular.

3. A water sensitive flow monitor element for use in a system forsensing the presence of free water in a transient fluid, the systemincluding a vessel having a fluid inlet and a fluid outlet, theimprovement comprising: a mass of algin material permitting the passageof hydrocarbon fluids therethrough while swelling upon the presence offree water; and fluid pervious means disposed within the vessel forcontaining said mass of algin material, said means having at least twospaced apart surfaces, one of said surfaces in communication with thefluid inlet of said vessel and the other of said surfaces incommunication with the fluid outlet of said vessel. 4. The inventiondefined in claim 3 wherein said fluid pervious means is cylindrical inshape.

5. The invention defined in claim 4 wherein said fluid pervious meansincludes:

a helical spring; a cylindrical sleeve of screen material disposedcoaxially about said spring; and a cylindrical mass of fiber glassmaterial disposed in concentric spaced relation about said cylindricalsleeve defining a space therebetween for containing said mass of watersensitive algin material. 6. The invention defined in claim 5 whereinsaid fluid pervious means includes: an outer cylindrical fluid perviousscreen formed about the outermost surface of said cylindrical mass offiber glass material.

7. The invention defined in claim 6 wherein said outer screen isplastic.

8. The invention defined in claim 7 wherein said outer screen is apolyethylene plastic material.

9. The invention defined in claim 8 including a solid plastic end capclosing ofl one end of said cylindrical fluid pervious means, and anapertured plastic end cap closing off the other end of said cylindricalfluid pervious means.

References Cited UNITED STATES PATENTS 556,578 3/1896 Iseli 2l05023,117,925 1/1964 Kasten 210-96 3,237,771 3/ 1966 Greenawalt 2l096 JOHNW. ADEE, Primary Examiner U.S. Cl. X.R.

